The area of the shadow of a body on a plane, also called the "outer quermass."
Brightness
See also
Aleksandrov's Uniqueness Theorem, Inner Quermass, Shadow, Shephard's Problem, TomographyExplore with Wolfram|Alpha
References
Blaschke, W. Kreis und Kugel. New York: Chelsea, p. 140, 1949.Bonnesen, T. "Om Minkowski's uligheder fur konvexer legemer." Mat. Tidsskr. B, 80, 1926.Bonnesen, R. and Fenchel, W. Theorie der Konvexer Körper. New York: Chelsea, p. 140, 1971.Chakerian, G. D. "Is a Body Spherical If All Its Projections Have the Same I.Q.?" Amer. Math. Monthly 77, 989-992, 1970.Croft, H. T.; Falconer, K. J.; and Guy, R. K. Unsolved Problems in Geometry. New York: Springer-Verlag, p. 23, 1991.Firey, W. J. "Blaschke Sum of Convex Bodies and Mixed Bodies." In Proceedings of the Colloquium on Convexity (Ed. W. Fenchel). Copenhagen, Denmark: Københavns Univ. Math. Inst., pp. 94-101, 1967.Referenced on Wolfram|Alpha
BrightnessCite this as:
Weisstein, Eric W. "Brightness." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Brightness.html